They did a good job making the movie look like it was in the '30's. Dillinger is depicted rather sympatheically, though if they didn't the whole story is that of just that of a bank robber. They did take some liberty with the facts later in the movie towards that end:
Spoiler
Baby Face Nelson didn't die at the Little Bohemia Lodge, but in fact after Dillinger's death succeeded him as Public Enemy #1 for six months; until Nelson was in turn gunned down.
